Uppermost mantle velocity from Pn tomography in the Gulf of Aden

Jordane Corbeau (1) , Frédérique Rolandone (1) , Sylvie Leroy (1) , A. Al-Lazki (2, 3) , A.L. Stork (4) , Derek Keir (5) , G.W. Stuart (6) , J.O.S. Hammond (7) , Cécile Doubre (8) , J. Vergne (8) , Abdulhakim Ahmed (1, 9) , Khaled Khanbari (10)

1 iSTeP - Institut des Sciences de la Terre de Paris
2 Department of Earth Sciences [Oman]
3 Exploration Department
4 School of Earth Sciences [Bristol]
5 National Ocenalography Centre Southampton
6 SEE - School of Earth and Environment [Leeds]
7 Department of Earth Science and Engineering [Imperial College London]
8 IPGS - Institut de physique du globe de Strasbourg
9 Seismological and Volcanological
10 Yemen Remote Sensing Center and Department of Earth and Environmental Science

We determine the lateral variations in seismic velocity of the lithospheric mantle beneath the Gulf of Aden and its margins by inversion of Pn (upper mantle high-fre- quency compressional P wave) traveltimes. Data for this study were collected by sev- eral temporary seismic networks and from the global catalogue. A least-squares tomo- graphic algorithm is used to solve for veloc- ity variations in the mantle lithosphere. In order to separate shallow and deeper struc- tures, we use separate inversions for shorter and longer ray path data. High Pn velocities (8.2-8.4 km/s) are observed in the uppermost mantle beneath Yemen that may be related to the presence of magmatic underplating of the volcanic margins of Aden and the Red Sea. Zones of low velocity (7.7 km/s) are present in the shallow upper mantle beneath Sana'a, Aden, Afar, and along the Gulf of Aden that are likely related to melt transport through the lithosphere feeding active volcanism. Deeper within the upper mantle, beneath the Oman margin, a low-velocity zone (7.8 km/s) suggests a deep zone of melt accumulation. Our results provide evidence that the asthe- nosphere undergoes channelized flow from the Afar hotspot toward the east along the Aden and Sheba Ridges.

Domaines: Sciences de la Terre

Jordane Corbeau, Frédérique Rolandone, Sylvie Leroy, A. Al-Lazki, A.L. Stork, et al.. Uppermost mantle velocity from Pn tomography in the Gulf of Aden. Geosphere, 2014, 10 (5), pp.1-11. ⟨10.1130/GES01052.1⟩. ⟨hal-01063921⟩